Battery shell and battery

Abstract

The invention belongs to the technical field of batteries, and discloses a battery shell and a battery, the battery shell comprises a shell body and a cover plate, thermoplastic material coatings are arranged on the sides, facing a pole group, of the cover plate and the shell body, and the cover plate and the shell body are connected in a heat source heating mode. The coating thickness h1 of the thermoplastic material coating arranged on the cover plate meets the condition that H is larger than or equal to 20 microns and smaller than or equal to 300 microns, and the coating thickness h2 of the thermoplastic material coating arranged on the shell body meets the condition that h2 is larger than or equal to 20 microns and smaller than or equal to 300 microns. The thermoplastic material coating is melted in a heat source heating mode, the cover plate and the shell body are connected into a whole, on one hand, when thermal runaway occurs, the thermoplastic material coating is melted at high temperature, high-temperature and high-pressure gas directly bursts through the cover plate to be discharged into the external environment, and the pressure relief protection performance is improved; the polar material is prevented from being contacted with the battery shell, and the corrosion resistance of the battery shell is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery casing and a battery. Background Art

[0002] For batteries, the battery casing and the electrode group are indispensable structures that constitute the battery, in which the electrode group and the battery casing together constitute a complete battery. The electrode group is the core component of the battery, responsible for storing and releasing electrical energy. The electrode group is mainly composed of positive electrode materials, negative electrode materials, electrolytes, and diaphragms. The electrode group is the smallest unit of the power battery and also the energy storage unit. It must have a high energy density to store as much electrical energy as possible; the battery casing is a container that wraps the electrode group. It not only provides physical protection to prevent the electrode group from being affected by the external environment, but also helps the electrode group dissipate heat and maintain the stability of the battery. Therefore, the performance of the battery casing has an important impact on the assembly, safety and performance of the battery.

[0003] Among them, the battery shell of the traditional lithium-ion battery is composed of an aluminum shell and a cover plate by laser welding. Laser welding is used to realize the rapid and efficient assembly of the aluminum shell and the cover plate. However, the battery shell of this structure has two defects. On the one hand, the battery shell assembled by laser welding has a high shell pressure resistance. When thermal runaway occurs, it is extremely difficult to break through the weld. Even if an explosion-proof valve is provided on the battery shell, it cannot achieve the effect of instantaneous pressure relief. Therefore, the pressure relief protection capability is limited if the explosion-proof valve is relied on for pressure relief. On the other hand, various defects usually occur in the lithium-ion battery manufacturing process, such as diaphragm folding. , electrode piece falling off, die-cutting wiredrawing and other abnormal phenomena result in the negative electrode material of the assembled battery often coming into contact with the aluminum shell. Since the potential of the aluminum shell is higher than the potential of the negative electrode graphite, and there is usually abundant electrolyte inside the battery, the aluminum shell-negative electrode-electrolyte constitutes a complete primary battery. Inside the primary battery, due to the contact between the aluminum shell and the negative electrode material, the lithium ions inside the negative electrode will migrate toward the aluminum shell under the drive of the electric potential, and be embedded in the aluminum shell to form a lithium-aluminum alloy, forming an electrochemical corrosion phenomenon, reducing the strength of the aluminum shell, causing the aluminum shell to leak under the erosion of electrochemical corrosion, resulting in battery failure and reduced service life. Summary of the invention

[0004] The object of the present invention is to provide a battery casing and a battery with good pressure relief protection, strong corrosion resistance and long service life.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] On the one hand, a battery shell is provided, the battery shell comprising a shell body and a cover plate, the shell body is a hollow shell structure with an opening, the cover plate is arranged at the opening of the shell body and closes the shell body to form a receiving cavity for storing an electrode group, the cover plate and the shell body are both provided with a thermoplastic material coating on one side facing the electrode group, the cover plate and the shell body are connected by heating with a heat source, and the thermoplastic material coating is used to bond the cover plate and the shell body;

[0007] The coating thickness of the thermoplastic material coating provided on the cover plate is h1, and satisfies 20um≤h1≤300um;

[0008] And / or, the coating thickness of the thermoplastic material coating provided on the shell body is h2, and satisfies 20um≤h2≤300um.

[0009] Optionally, the wall thickness dimension of the cover plate is H1, and satisfies 0.02≤h1 / H1≤0.2.

[0010] Optionally, the wall thickness dimension of the shell body is H2, and satisfies 0.05≤h2 / H2≤0.5.

[0011] Optionally, the heating temperature of the cover plate and the shell body connected by heat source heating is T, and satisfies, T f +20℃≤T≤T f +150℃, where T f is the viscous flow temperature of the thermoplastic coating.

[0012] Optionally, the heat source for heating is non-contact or contact.

[0013] Optionally, a distance dimension between the non-contact heat source and a connection between the cover plate and the shell body is D, and D≥1 mm.

[0014] Optionally, the heat source heats the connection between the cover plate and the shell body for a time period of X, and X≥5s.

[0015] Optionally, the cover plate and the shell body connected by heating have a cooling time after heating of Y, and Y≥3s.

[0016] Optionally, the thermoplastic material coating is a PP coating or a PE coating.

[0017] On the other hand, a battery is provided, comprising a pole group and a battery casing as described in any one of the above items, wherein the pole group is arranged in the accommodating cavity in the battery casing.

[0018] Beneficial effects of the present invention:

[0019] The present invention provides a battery shell, wherein a thermoplastic material coating is arranged on the side of the cover plate and the shell body facing the electrode group, so that when the cover plate and the shell body are connected by heating with a heat source, the thermoplastic material coating arranged on the side of the cover plate and the shell body facing the electrode group melts and blends with each other, and after being left to cool for a period of time, the blended thermoplastic material coating cools and solidifies, and the cover plate and the shell body are connected as a whole. The cover plate and the shell body connected by the thermoplastic material coating, on the one hand, when thermal runaway occurs, the high temperature can melt the thermoplastic material coating, thereby weakening the connection between the shell body and the cover plate. The connection strength is improved so that when the explosion-proof valve cannot meet the pressure relief demand, the high-temperature and high-pressure gas can directly break through the cover plate and be discharged into the external environment, thereby improving the pressure relief protection of the battery shell. On the other hand, the thermoplastic material coating is used to form a protective layer in the accommodating cavity to avoid electrochemical corrosion caused by the contact between the polar material and the shell body, thereby enhancing the corrosion resistance of the battery shell. In addition, by limiting the coating thickness h1 of the thermoplastic material coating on the cover plate and the coating thickness h2 of the thermoplastic material coating on the shell body, it is ensured that they have sufficient thickness to maintain strong corrosion resistance and connection strength.

[0020] The present invention also provides a battery, which, by applying the above-mentioned battery shell, has good pressure relief protection and corrosion resistance, thereby reducing the probability of battery failure and extending the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a cover plate provided with a thermoplastic material coating in a battery housing provided by the present invention;

[0022] Figure 2 It is a structural cross-sectional view of a battery shell provided by the present invention, wherein the shell body is provided with a thermoplastic material coating;

[0023] Figure 3 It is a top view of a battery shell provided by the present invention, in which a shell body is provided with a thermoplastic material coating.

[0024] In the figure:

[0025] 1. Shell body;

[0026] 2. Cover plate; 21. Positive pole; 22. Negative pole;

[0027] 3. Thermoplastic material coating. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0029] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0031] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0032] For batteries, the battery casing and the electrode group are indispensable structures that constitute the battery, in which the electrode group and the battery casing together constitute a complete battery. The electrode group is the core component of the battery, responsible for storing and releasing electrical energy. The electrode group is mainly composed of positive electrode materials, negative electrode materials, electrolytes, and diaphragms. The electrode group is the smallest unit of the power battery and also the energy storage unit. It must have a high energy density to store as much electrical energy as possible; the battery casing is a container that wraps the electrode group. It not only provides physical protection to prevent the electrode group from being affected by the external environment, but also helps the electrode group dissipate heat and maintain the stability of the battery. Therefore, the performance of the battery casing has an important impact on the assembly, safety and performance of the battery.

[0033] Among them, the battery shell of the traditional lithium-ion battery is composed of an aluminum shell and a cover plate by laser welding. Laser welding is used to realize the rapid and efficient assembly of the aluminum shell and the cover plate. However, the battery shell of this structure has two defects. On the one hand, the battery shell assembled by laser welding has a high shell pressure resistance. When thermal runaway occurs, it is extremely difficult to break through the weld. Even if an explosion-proof valve is provided on the battery shell, it cannot achieve the effect of instantaneous pressure relief. Therefore, the pressure relief protection capability is limited if the explosion-proof valve is relied on for pressure relief. On the other hand, various defects usually occur in the lithium-ion battery manufacturing process, such as diaphragm folding. , electrode piece falling off, die-cutting wiredrawing and other abnormal phenomena result in the negative electrode material of the assembled battery often coming into contact with the aluminum shell. Since the potential of the aluminum shell is higher than the potential of the negative electrode graphite, and there is usually abundant electrolyte inside the battery, the aluminum shell-negative electrode-electrolyte constitutes a complete primary battery. Inside the primary battery, due to the contact between the aluminum shell and the negative electrode material, the lithium ions inside the negative electrode will migrate toward the aluminum shell under the drive of the electric potential, and be embedded in the aluminum shell to form a lithium-aluminum alloy, forming an electrochemical corrosion phenomenon, reducing the strength of the aluminum shell, causing the aluminum shell to leak under the erosion of electrochemical corrosion, resulting in battery failure and reduced service life.

[0034] Therefore, in order to improve the pressure relief protection and corrosion resistance of the battery casing and extend the service life, this embodiment provides a battery casing.

[0035] like Figures 1 to 3 As shown, the battery shell includes a shell body 1 and a cover plate 2, the shell body 1 is a hollow shell structure with an opening, the cover plate 2 is covered at the opening of the shell body 1, and closes the shell body 1 to form a receiving cavity for storing the electrode group, the cover plate 2 and the shell body 1 are both provided with a thermoplastic material coating 3 on one side facing the electrode group, the cover plate 2 and the shell body 1 are connected by heating with a heat source, the thermoplastic material coating 3 is used to bond the cover plate 2 and the shell body 1, and the coating thickness of the thermoplastic material coating 3 provided on the cover plate 2 is h1, and satisfies, 20um≤h1≤300um;

[0036] And / or, the coating thickness of the thermoplastic material coating 3 provided on the housing body 1 is h2, and satisfies 20um≤h2≤300um.

[0037] The battery shell is provided with a thermoplastic material coating 3 on the side of the cover plate 2 and the shell body 1 facing the electrode group, so that when the cover plate 2 and the shell body 1 are connected by heating with a heat source, the thermoplastic material coating 3 provided on the side of the cover plate 2 and the shell body 1 facing the electrode group melts and blends with each other. After being left to cool for a period of time, the blended thermoplastic material coating 3 cools and solidifies, and the cover plate 2 and the shell body 1 are connected as a whole. The cover plate 2 and the shell body 1 connected by the thermoplastic material coating 3, on the one hand, when thermal runaway occurs, the high temperature can melt the thermoplastic material coating 3, thereby weakening the connection strength between the shell body 1 and the cover plate 2. The degree of high temperature and high pressure gas can directly break through the cover plate 2 and be discharged into the external environment when the explosion-proof valve cannot meet the pressure relief demand, thereby improving the pressure relief protection of the battery shell. On the other hand, the thermoplastic material coating 3 is used to form a protective layer in the accommodating cavity, thereby avoiding electrochemical corrosion caused by the contact between the polar material and the shell body 1, thereby enhancing the corrosion resistance of the battery shell. In addition, by limiting the coating thickness h1 of the thermoplastic material coating 3 arranged on the cover plate 2 and the coating thickness h2 of the thermoplastic material coating 3 arranged on the shell body 1, it is ensured that they have sufficient thickness to maintain strong corrosion resistance and connection strength.

[0038] The thickness of the thermoplastic material coating 3 provided on the cover plate 2 and the thickness of the thermoplastic material coating 3 provided on the shell body may be the same or different, and is set according to actual needs. In the present embodiment, the coating thickness h1 of the thermoplastic material coating 3 provided on the cover plate 2 and the coating thickness h2 of the thermoplastic material coating 3 provided on the shell body 1 are the same.

[0039] The coating thickness h1 of the thermoplastic material coating 3 arranged on the cover plate 2 and the coating thickness h2 of the thermoplastic material coating 3 arranged on the shell body 1 can be any value between 20um and 300um or a range between any two values, for example, 20um, 40um, 60um, 80um, 100um, 120um, 140um, 160um, 180um, 200um, 220um, 240um, 260um, 280um, 300um, etc.

[0040] The battery shell can be applied to many different types of batteries, such as blade batteries, square shell batteries or large cylindrical batteries. In this embodiment, the battery shell is mainly used for square shell batteries, so the cover plate 2 is provided with a positive electrode column 21 and a negative electrode column 22, the positive electrode ear on the electrode group passes through the thermoplastic material coating 3 to connect with the positive electrode column 21, and the negative electrode ear on the electrode group passes through the thermoplastic material coating 3 to connect with the negative electrode column 22, wherein the thermoplastic material coating 3 can not only realize corrosion protection, but also the solidified thermoplastic material can realize the fixation of the positive electrode ear and the negative electrode ear, so as to avoid the positive electrode ear and the negative electrode ear from being dislocated internally due to external vibration, and ensure the accuracy of the connection position of the two.

[0041] In this embodiment, the heat source used for heating can be non-contact or contact, and its specific form can be freely selected according to the working environment, and the thermoplastic material coating 3 can be PP coating or PE coating, or other thermoplastic material coating.

[0042] Alternatively, if Figure 1 As shown, the wall thickness of the cover plate 2 is H1, and 0.02≤h1 / H1≤0.2 is satisfied. By limiting the ratio between the coating thickness h1 of the thermoplastic coating 3 and the wall thickness H1 of the cover plate 2, it is possible to avoid the coating thickness of the thermoplastic coating 3 applied on the cover plate 2 being too small, resulting in poor corrosion resistance, and to avoid the coating thickness of the thermoplastic coating 3 applied on the cover plate 2 being too large, wasting materials and occupying a large space.

[0043] Alternatively, if Figure 2 As shown, the wall thickness dimension of the shell body 1 is H2, and satisfies 0.05≤h2 / H2≤0.5. By limiting the ratio between the coating thickness h2 of the thermoplastic coating 3 and the wall thickness dimension H2 of the shell body 1, it is possible to avoid, on the one hand, the coating thickness of the thermoplastic coating 3 applied on the shell body 1 being too small, resulting in poor corrosion resistance, and on the other hand, to avoid the coating thickness of the thermoplastic coating 3 applied on the shell body 1 being too large, wasting materials and occupying a large space.

[0044] Optionally, the heating temperature of the cover plate 2 and the housing body 1 connected by heat source heating is T, and satisfies T f +20℃≤T≤T f +150℃, where T f is the viscous flow temperature of the thermoplastic material coating 3. By limiting the heating temperature T of the heat source, it satisfies T f +20℃≤T≤T f +150°C, so that the heating temperature T is always higher than the viscosity temperature T of the thermoplastic material coating 3 during heating f, thereby ensuring that the thermoplastic material coating 3 is in a molten state when the cover plate 2 and the shell body 1 are heated and connected, making it convenient to bond and fix the cover plate 2 and the shell body 1.

[0045] In this embodiment, the viscosity temperature T of the thermoplastic coating 3 is f Usually at 120℃<T f <250°C, where the glass transition temperature of the thermoplastic coating 3 is T g , and satisfies T g ≤100°C, so in order to ensure that the thermoplastic coating 3 solidifies after heating, the ambient temperature of the thermoplastic coating 3 should be lower than the glass transition temperature T g .

[0046] Optionally, the distance dimension D between the non-contact heat source and the connection between the cover plate 2 and the shell body 1 is D, and satisfies D≥1mm. A non-contact heat source is used, and the distance dimension D between the non-contact heat source and the connection between the cover plate 2 and the shell body 1 is limited to satisfy D≥1mm, thereby avoiding the non-contact heat source being too far away from the connection between the cover plate 2 and the shell body 1, resulting in slow heating, low heating efficiency, and long heating time. The distance dimension D can be 1mm, 2mm, 3mm, 4mm, 5mm, etc.

[0047] Optionally, the heating time X of the connection between the cover plate 2 and the shell body 1 by the heat source is X, and X≥5s. By limiting the heating time X of the connection between the cover plate 2 and the shell body 1 by the heat source to satisfy X≥5s, it is avoided that the heating time is too short, resulting in insufficient melting of the thermoplastic material coating 3, wherein the heating time X can be 5s, 6s, 7s, 8s, 9s, 10s, etc.

[0048] Optionally, the cover plate 2 and the shell body 1 connected by heating have a cooling time Y after heating, and Y≥3s. The cooling time Y after heating is limited to satisfy Y≥3s, thereby avoiding the situation where the thermoplastic material coating 3 in the molten state has not yet solidified due to the cooling time being too short, wherein the cooling time Y can be 3s, 4s, 5s, 6s, etc.

[0049] In this embodiment, in order to verify the influence of the ratio of the coating thickness h1 of the thermoplastic material coating 3 provided on the cover plate 2 to the wall thickness dimension H1 of the cover plate 2 and the ratio of the coating thickness h2 of the thermoplastic material coating 3 provided on the shell body 1 to the wall thickness dimension H2 of the shell body 1 on the product quality, as shown in Table 1, seven groups of embodiments and three groups of comparative examples are provided for verification. During the experiment, the heating temperature is set to 195°C, the heating time is set to 10s, and the cooling time is set to 15s.

[0050] Table 1

[0051]

[0052] In Example 1, the coating thickness of the thermoplastic material coating 3 on the cover plate 2 is set to h1=60um, and h1 / H1 is set to 0.03. The wall thickness dimension H1 obtained at this time is 2mm. The thickness of the thermoplastic material coating 3 on the outer shell body 1 is set to h2=40um, and h2 / H2 is set to 0.05. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface. No deformation of the battery shell is found after hot melting. There is no problem of poor insulation. The product is qualified.

[0053] In Example 2, the coating thickness h1 of the thermoplastic material coating 3 on the cover plate 2 is set to 200um, and h1 / H1 is set to 0.1. The wall thickness dimension H1 obtained at this time is 2mm. The thickness h2 of the thermoplastic material coating 3 on the outer shell body 1 is set to 200um, and h2 / H2 is set to 0.25. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface. No deformation of the battery shell is found after hot melting. There is no problem of poor insulation. The product is qualified.

[0054] In Example 3, the coating thickness h1 of the thermoplastic material coating 3 on the cover plate 2 is set to 150um, and h1 / H1 is set to 0.075. The wall thickness dimension H1 obtained at this time is 2mm. The thickness h2 of the thermoplastic material coating 3 on the outer shell body 1 is set to 200um, and h2 / H2 is set to 0.25. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface. No deformation of the battery shell is found after hot melting. There is no problem of poor insulation. The product is qualified.

[0055] In Example 4, the coating thickness h1 of the thermoplastic material coating 3 on the cover plate 2 is set to 100um, and h1 / H1 is set to 0.05. The wall thickness dimension H1 obtained at this time is 2mm. The thickness h2 of the thermoplastic material coating 3 on the outer shell body 1 is set to 150um, and h2 / H2 is set to 0.1875. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface. No deformation of the battery shell is found after hot melting. There is no problem of poor insulation. The product is qualified.

[0056] In Example 5, the coating thickness of the thermoplastic material coating 3 on the cover plate 2 is set to h1=80um, and h1 / H1 is set to 0.04. The wall thickness dimension H1 obtained at this time is 2mm. The thickness of the thermoplastic material coating 3 on the outer shell body 1 is set to h2=100um, and h2 / H2 is set to 0.125. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface. No deformation of the battery shell is found after hot melting. There is no problem of poor insulation. The product is qualified.

[0057] In Example 6, the coating thickness of the thermoplastic material coating 3 on the cover plate 2 is set to h1=250um, and h1 / H1 is set to 0.125. The wall thickness dimension H1 obtained at this time is 2mm. The thickness of the thermoplastic material coating 3 on the outer shell body 1 is set to h2=50um, and h2 / H2 is set to 0.0625. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface. No deformation of the battery shell is found after hot melting. There is no problem of poor insulation. The product is qualified.

[0058] In Example 7, the coating thickness h1 of the thermoplastic material coating 3 on the cover plate 2 is set to 175um, h1 / H1 is set to 0.875, and the wall thickness dimension H1 obtained at this time is 2mm. The thickness h2 of the thermoplastic material coating 3 on the outer shell body 1 is set to 100um, h2 / H2 is set to 0.125, and the wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface, no deformation of the battery shell is found after hot melting, and no poor insulation problem occurs. The product is qualified.

[0059] It can be seen from Examples 1 to 7 that when the coating thickness of the thermoplastic material coating 3 provided on the cover plate 2 is h1 and satisfies 20um≤h1≤300um, and the coating thickness of the thermoplastic material coating 3 provided on the outer shell body 1 is h2 and satisfies 20um≤h2≤300um, its thickness meets the insulation requirements, and the amount of glue is moderate, and it will not overflow to the outer surface of the battery shell after hot melting. And when the ratio h1 / H1 of the coating thickness h1 of the thermoplastic material coating 3 provided on the cover plate 2 and the wall thickness dimension H1 of the cover plate 2 and the ratio h2 / H2 of the coating thickness h2 of the thermoplastic material coating 3 provided on the outer shell body 1 respectively meet their respective corresponding ranges, the obtained thickness of the cover plate 2 and the thickness of the outer shell body 1 meet the use requirements, have sufficient structural strength, and avoid deformation during hot melting.

[0060] In Comparative Example 1, the coating thickness of the thermoplastic material coating 3 on the cover plate 2 is set to h1=500um, and h1 / H1 is set to 0.25. The wall thickness dimension H1 obtained at this time is 2mm. The thickness of the thermoplastic material coating 3 on the outer shell body 1 is set to h2=350um, and h2 / H2 is set to 0.4375. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested and no deformation is found after hot melting, and no poor insulation problem occurs. However, glue overflow is found on the outer surface of the battery shell, and the product is unqualified.

[0061] It can be seen from Comparative Example 1 that when the coating thickness of the thermoplastic material coating 3 provided on the cover plate 2 is h1 greater than the maximum value of 20um≤h1≤300um, and the coating thickness of the thermoplastic material coating 3 provided on the outer shell body 1 is h2 greater than the maximum value of 20um≤h2≤300um, the amount of glue is too much at this time, causing the hot melt to overflow onto the outer surface of the battery shell.

[0062] In Comparative Example 2, the coating thickness h1 of the thermoplastic material coating 3 on the cover plate 2 is set to 15um, and h1 / H1 is set to 0.0075. The wall thickness dimension H1 obtained at this time is 2mm. The thickness h2 of the thermoplastic material coating 3 on the outer shell body 1 is set to 15um, and h2 / H2 is set to 0.01875. The wall thickness dimension H2 obtained at this time is 0.8mm. After the assembly is completed, the battery shell is tested. After hot melting, no glue overflow is found on the outer surface of the battery shell, and no deformation of the battery shell is found, but poor insulation occurs, and the product is unqualified.

[0063] It can be seen from Comparative Example 2 that when the coating thickness of the thermoplastic material coating 3 provided on the cover plate 2 is h1 less than the minimum value of 20um≤h1≤300um, and the coating thickness of the thermoplastic material coating 3 provided on the shell body 1 is h2 less than the minimum value of 20um≤h2≤300um, the amount of glue is too small, resulting in the formation of an insulating layer with a too small thickness, which is broken down by the current during use, resulting in poor insulation.

[0064] In Comparative Example 3, the coating thickness of the thermoplastic material coating 3 on the cover plate 2 is set to h1=200um, and h1 / H1 is set to 0.6. The wall thickness dimension H1 obtained at this time is 0.3mm. The thickness of the thermoplastic material coating 3 on the outer shell body 1 is set to h2=250um, and h2 / H2 is set to 0.8. The wall thickness dimension H2 obtained at this time is 0.3mm. After the assembly is completed, the battery shell is tested and no glue overflow is found on the outer surface of the battery shell, and no poor insulation problem occurs. However, the battery shell is deformed after hot melting, and the product is unqualified.

[0065] It can be seen from Comparative Example 3 that when the ratio h1 / H1 of the coating thickness h1 of the thermoplastic material coating 3 provided on the cover plate 2 to the wall thickness dimension H1 of the cover plate 2 and the ratio h2 / H2 of the coating thickness h2 of the thermoplastic material coating 3 provided on the outer shell body 1 are both greater than the maximum value of their respective ranges, the wall thickness dimension H1 of the cover plate 2 and the wall thickness dimension H2 of the outer shell body 1 obtained at this time are too small, so that the structural strength is weak, resulting in deformation after hot melting, resulting in poor appearance.

[0066] In this embodiment, a battery is also provided, which includes an electrode group and the above-mentioned battery shell, and the electrode group is arranged in the accommodating cavity in the battery shell. By using the above-mentioned battery shell, the battery has good pressure relief protection and corrosion resistance, thereby reducing the probability of battery failure and extending the service life of the battery.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery housing, characterized in that: The battery shell comprises a shell body and a cover plate, wherein the shell body is a hollow shell structure with an opening, the cover plate is arranged at the opening of the shell body and closes the shell body to form a receiving cavity for storing the electrode group, the cover plate and the side of the shell body facing the electrode group are both provided with a thermoplastic material coating, the cover plate and the shell body are connected by heating with a heat source, and the thermoplastic material coating is used to bond the cover plate and the shell body; The coating thickness of the thermoplastic material coating provided on the cover plate is h1, and satisfies 20um≤h1≤300um; And / or, the coating thickness of the thermoplastic material coating provided on the shell body is h2, and satisfies 20um≤h2≤300um.

2. The battery housing according to claim 1, characterized in that: The wall thickness dimension of the cover plate is H1, and satisfies 0.02≤h1 / H1≤0.

2.

3. The battery housing according to claim 1, characterized in that: The wall thickness dimension of the shell body is H2, and satisfies 0.05≤h2 / H2≤0.

5.

4. The battery housing according to claim 1, characterized in that: The heating temperature of the cover plate and the shell body connected by heat source heating is T, and satisfies, T f +20℃≤T≤T f +150℃, where T f is the viscous flow temperature of the thermoplastic coating.

5. The battery housing according to claim 1, characterized in that: The heat source used for heating is non-contact type or contact type.

6. The battery housing according to claim 5, characterized in that: The distance dimension between the non-contact heat source and the connection between the cover plate and the shell body is D, and D≥1mm.

7. The battery housing according to claim 1, characterized in that: The heat source heats the connection between the cover plate and the shell body for a time period of X, and X≥5s.

8. The battery housing according to claim 1, characterized in that: The cover plate and the shell body connected by heating have a cooling time after heating of Y, and Y≥3s.

9. The battery housing according to claim 1, characterized in that: The thermoplastic material coating is a PP coating or a PE coating.

10. A battery, characterized in that The battery comprises a pole group and a battery casing as claimed in any one of claims 1 to 9, wherein the pole group is arranged in the accommodating cavity in the battery casing.

Images